Search academic texts

Information × Registration Number 0217U001269, 0115U000478 , R & D reports Title Kinetics of interface interactions and diffusion processes in layered film nanosystems popup.stage_title Head Kryshtal Oleksandr, Registration Date 02-02-2017 Organization Kharkov National University named after V.N. Karazin popup.description2 Objective: solving the scientific problem of physical regularities in the phase state and the diffusion mobility of the components in nanoscale layered films of Cu (50 atomic %) - Ni. Object under study: nanoscale multilayer film systems Cu (50 at.%.)/Ni with layers mass thickness of 5-100 nm and constant total thickness of 200 nm. Subject of research: the speed of diffusion processes in the nanodispersed films, the influence of a size factor on the activation energy of diffusion in the film systems, morphology and phase structure of the layered films. Research methods: In situ samples' electric resistivity measuring, in situ transmission electron microscopy, electron diffraction, X-ray spectroscopy. Experimental results concerning the size dependence of the grain-boundary diffusion activation energy in layered films of Cu - Ni have been presented. The study was fulfilled using the in situ method of measuring samples' electric resistance. It was found that the activation energy of diffusion processes is size-depended and decreases with the characteristic size of the system reduction. The activation energy size dependence (vs layer thicknesses) has been plotted in a range of 5 to 100 nm. In particular, the activation energy of grain-boundary diffusion in a system with a layer thickness of 5 nm has been estimated as ? 0.3 eV. This value is significantly lower than the corresponding to macroscopic samples one (1.26 - 1.30 eV). Calculation of the effective diffusion coefficients yielded a significant acceleration of diffusion processes in nanodispersed films: the integral diffusion coefficient in the sample with a characteristic size of 5 nm is 10 orders of magnitude greater than macroscopic samples' one. This acceleration can be explained in a frame of the vacancy diffusion mechanism. Data on the morphology evolution of a layered film system Cu/Ni caused be thermal treatment have been obtained using in situ TEM examination and also presented. The main results obtained for the first time, their relevance is due to both the need to understand the processes in the physics of low-dimensional systems and the widespread use of such objects in modern technologies. Results of research can be used by academic institutions engaged in similar studies. Product Description popup.authors О. Кришталь О. Мінєнков Р. Сухов С. Богатиренко popup.nrat_date 2020-04-02 Close